Whistling or Screeching Noises in Pipes

This hub covers whistling, squealing, or screeching noises that occur while water is flowing from fixtures. These sounds often point to a restriction or valve behavior that shows up only at certain flow rates—for example when a valve is partially open, during peak demand, or when two fixtures run at once. Use the groups below to match where the noise seems to come from and what changed recently, then open the closest article title.

Related sub-category: Air, Noise & Vibration in Pipes

Faucet, toilet, shower, and dishwasher sources

Noises tied directly to common fixtures, their valves, or filling mechanisms.

• Faucet whistles when turned on

  Often caused by a worn cartridge, loose seat, or debris in an aerator; symptoms usually appear at particular flow rates.

• Toilet squeals while refilling

  Squealing during the tank refill commonly points to the fill valve or inlet assembly and may occur until the float shuts the valve off.

• Squealing from toilet at night

  Intermittent night-time noises can be due to slow leaks or cycling fill valves that operate quietly during lower household demand.

• High-pitched noise from shower valve

  Shower valve squeals typically come from the cartridge or a pressure-related restriction inside the valve body.

• High-pitch noise when filling bathtub

  Bathtub fill noises often occur when the valve is partially open or when flow meets an obstruction in the spout or mixer.

• Whistling noise when dishwasher fills

  Dishwasher fill whistle usually traces to the solenoid valve or a nearby restriction; it often coincides with the appliance’s fill cycle.

Hot-only, cold-only, or multi-fixture effects

Use which side or how many fixtures run to narrow the source.

• Whistling only on cold water

  Cold-side-only noise suggests an issue in the cold plumbing run, valve, or a cold-only supply component like a filter or stop.

• Whistling only on hot water

  Hot-side noises point to the water heater outlet, a mixing valve, or deposits in the hot supply line restricting flow.

• Whistling when two fixtures run

  Noise that appears only when two fixtures operate together often indicates a partial restriction or pressure drop in the common supply line.

After changes at the outlet or supply

Noises that begin immediately after installing parts or after any supply-side work.

• Whistling after installing aerator

  An aerator can trap debris or create a new flow pattern that whistles; removal and cleaning often diagnose the issue.

• High-pitched noise after installing filter

  After adding a filter, reduced flow or a vibrating element in the filter housing can produce high-frequency noise.

• Screeching after replacing angle stop

  New stops can have rough seats or slight misalignment that whistle until they bed in or are adjusted.

• Whistling after PRV replacement

  Pressure-reducing valve changes can alter flow characteristics; a misadjusted PRV or internal seat can whistle under certain flows.

• Whistling started after city work

  Work on the main can dislodge debris or change pressure, producing temporary whistles until the system settles or is flushed.

Inside walls or outdoor connections

Noises that seem to originate from wall cavities, exterior hose bibs, or hose connections.

• Screeching noise inside wall

  Wall-cavity noises often come from a running valve or a localized restriction and can be harder to access for inspection.

• Screeching when hose connected

  Hose-thread or quick-connect fittings can create a whistle when flow interacts with the connection or an inline valve.

Behavior clues

Patterns that change with valve position or during high-demand periods help identify whether the issue is flow- or pressure-related.

• Noise stops when valve opened fully

  If noise disappears with the valve fully open, the problem is likely a partial restriction or a valve component vibrating at intermediate positions.

• Squealing during peak hours

  Squealing only at peak times suggests supply pressure or demand-related flow changes, sometimes tied to the main or a PRV setting.

All Articles in This Cluster

• Faucet whistles when turned on
• Toilet squeals while refilling
• Squealing from toilet at night
• High-pitched noise from shower valve
• High-pitch noise when filling bathtub
• Whistling noise when dishwasher fills
• Whistling only on cold water
• Whistling only on hot water
• Whistling when two fixtures run
• Whistling after installing aerator
• High-pitched noise after installing filter
• Screeching after replacing angle stop
• Whistling after PRV replacement
• Whistling started after city work
• Screeching noise inside wall
• Screeching when hose connected
• Noise stops when valve opened fully
• Squealing during peak hours